粗糙壁湍流的研究
首发时间:2011-01-10
摘要:采用声学多普勒流速仪(ADV),研究了不同粒径粗糙元下游流向平均速度和湍流度的变化规律。实验中在光滑壁面上沿展向均匀布置一排球形粗糙元,基于平均速度和水力直径的雷诺数为36000,离散粗糙元直径分别为2.3、6和10mm,粗糙元间距为2cm。实验发现:相比光滑壁面,放置粗糙元后其下游流向平均速度减小,湍流度增大。粗糙元粒径越大,下游相同截面处的流向平均速度越小、湍流度越大,对流向和法向的平均流向速度和湍流度的影响范围也越大。该研究结果对壁湍流的流动控制工程应用具有重要指导和参考价值。
关键词: 流体力学 壁湍流 声学多普勒流速仪(ADV) 粗糙元 湍流度 流动控制
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Study on effects of wall roughness on turbulence
Abstract:This paper investigates effects of roughness elements on the near-wall turbulence using ADV. The roughness elements row is located on the bottom wall uniformly. The Reynolds number, based on the mean velocity and channel hydraulic diameter, is 36000, and the roughness elements are spheres in diameter of 2.3, 6 and 10mm arranged at intervals of 2cm in the spanwise direction. The flow mean velocity is decrease but the turbulence intensity is increased for the roughness wall compared with the smooth wall. The larger the roughness element diameter is, the smaller the mean velocity and the higher the turbulence intensity downstream the roughness. The larger roughness element affects the flow more strongly. . This study is valuable for wall turbulence flow control in engineering.
Keywords: fluid mechanics wall turbulence ADV roughness element turbulence intensity flow control
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No.4403411562970129****
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